Different sports have different rules for the audience(观众). For example, you have to keep quiet while you are watching badminton matches. But a cheering can really help basketball and football players. So it is a good idea to learn about the culture and rules of sports.
Here is some advice on how to be a good audience.
Read the ticket before you arrive. Try to reach your seat half an hour before the start of a game and don't walk about when the game is being held because you might disturb(打扰) other audience.
Using flash to take photos will influence tennis players. Mobile phones cannot be used in shooting centers.
During the marathon(马拉松), your cheering is important to the runners, but don't trouble them. Don't offer them food unless they ask for it